Medical procedures, such as deep brain stimulation, deep brain infusion, and biopsy procedures, often require mapping the trajectory of a medical device to reach a target point within a patient during the medical procedure. The target point may be, for example, a brain tumor that must be removed by the physician during surgery. A known system for performing trajectory alignment involves the use of a Navigus trajectory guide. A fluid filled stem is placed within the Navigus trajectory guide to monitor the trajectory using images displayed on a medical imaging viewing system, such as a Magnetic Resonance Imaging (MRI) viewing system connected to an MRI scanner. The Navigus trajectory guide is placed over the burr hole and is secured to the skull with three bone screws. Normally, a physician, located at the MRI scanner, manually adjusts the Navigus trajectory guide secured to the patient at the MRI scanner, while using instructions provided by the medical imaging technologist located at the MRI viewing system, to align the medical device with the trajectory defined by the target point. Once the adjustment is made, an additional MRI scan is performed to view the results of the adjustment. This process may take several attempts before the physician is able to appropriately align the medical device to reach the target point within the patient. Consequently, this process is time consuming because the physician performs the alignment based on the guidance of the medical technologist, each of whom are typically located in a separate room. This process is also dangerous for the patient due to possible negative long term effects of prolonged exposure to anesthesia.
A known system of performing trajectory alignment is stereotaxic targeting. With this system, the target point is determined using preoperative MRI images. From the images, the burr hole location is determined to accommodate insertion of the medical device along a generally vertical axis. Preferably, the burr hole is placed over non-essential brain tissue. The medical device is inserted through the burr hole using a micromanipulator on a stereotaxic frame. Unfortunately, this system does not accommodate off axis trajectories for placement of the medical device in irregularly shaped targets, such as the putamen, located at the base of the forebrain. An additional problem presented by this method is that the trajectory is determined based upon preoperative images, rather that images produced in real time.
Another known system, the arc-phantom system (a type of sterotaxic targeting) also involves several lengthy steps in performing the trajectory alignment. Using the arc-phantom system, initially, an aiming bow is attached to a head ring that is fixed to the patient's skull. The aiming bow can be transferred to a similar ring that contains a replicated target. The aiming bow is then adjusted to reach the desired replicated target. Once the replicated target is reached with the aiming bow, the system is placed back on the patient's skull.
Additional problems presented by many known trajectory alignment systems are difficult assembly and difficult adjustment of the trajectory alignment systems. Many of the known trajectory alignment systems involve several components that must be assembled prior to using the system. Likewise, many of the known targeting systems involve several steps and manipulation of components in order to perform the trajectory alignment of the medical device to reach the target point within the patient.
Therefore, a need exists to overcome the problems with the prior art as discussed above.